A kind of equipment and method for producing ethylene-vinyl acetate copolymer packaging film

Abstract

The invention provides a production equipment and method of ethylene-vinyl acetate copolymer packaging film (EVA). The EVA sheet is heated by adding an air flotation heating device between the extrusion device and the molding device in the existing production mode. Heating makes the sheet into a viscous fluid state, and the EVA macromolecular chain changes from an oriented state to a disoriented state, which eliminates internal stress and reduces the heat shrinkage rate of the finished EVA packaging film. The heating effect of the EVA sheet is better by using the air flotation heating device, and at the same time, the speed of the production line is significantly improved, and the production efficiency is improved.

Description

technical field [0001] The invention belongs to the technical field of plastic film production, and in particular relates to equipment for producing ethylene-vinyl acetate copolymer packaging films. Background technique [0002] At present, the production of ethylene-vinyl acetate copolymer (EVA) packaging film is mainly produced by extrusion casting or extrusion calendering. The main raw material EVA is plasticized into a melt by an extruder and then passed through a flat die to make the melt It is formed into an EVA sheet, and then passed through a silicone pressure roller and an embossed cold roller to shape and pull it into a winding device for winding to complete the production of the film. Since EVA is a macromolecular material, the macromolecular chains are easily arranged in parallel in a certain direction during the processing and molding process. This spontaneous orientation of the macromolecular chains causes internal stress in the film, and the internal stress wi...

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Problems solved by technology

Since EVA is a macromolecular material, the macromolecular chains are easily arranged in parallel in a certain direction during the processing and molding process. This spontaneous orientation of the macromolecular chains causes internal stress in the film, and the internal stress will cause the EVA packaging film to be easily damaged during subsequent use. Cracking due to heat shrinkage

[0003] The products produced by the existing EVA packaging film production method have a large heat shrinkage rate during use, and it is difficult to control the process to reduce the heat shrinkage rate of the product. Generally, the shrinkage rate of the EVA finished product can only be about 4%; due to heat shrinkage The rate is relatively high, and the use of EVA film in the packaging of silicon cells leads to cracks in the cells from time to time, resulting in a decrease in the yield of cells and an increase in production costs, and it will also seriously affect the yield of the subsequent lamination process.

In addition, limited by the existing production process and equipment, the speed of a single production line of a general manufacturer can only be below 3m / min, and the production efficiency is low

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